As the heroine of “Nim’s Island,” Abigail Breslin embodies a great kid fantasy — she’s smart, courageous, independent and she lives on a tropical island with her doting father (Gerard Butler) and a menagerie of pals, including a lizard, a seal and a pelican. Nim is a new millennium Pippi Longstocking with better hair and a Greenpeace card.

So why does “Nim’s Island” feel so charmless and rote? Perhaps it’s because the film feels like an amalgam of other movies’ plotlines; I started ticking off “Romancing the Stone,” “Play It Again, Sam,” “The Swiss Family Robinson” and “Home Alone” in my head when my attention wandered. And it wandered often.

Nim and her father Jack live on their very own island in the south Asiatic Sea, where Jack studies microscopic plankton. They both miss Nim’s oceanographer mother, who was apparently swallowed up by a whale, but their lives are otherwise idyllic. But when Jack leaves Nim alone for two days while he goes diving for samples, his boat gets caught in a storm that destroys his sail and his satellite phone.

Nim begins to panic, not only because of her father’s absence, but because their secret island is on the verge of being overrun by “buccaneers,” who turn out to be agents of a cruise line who want to overrun the place with sunburned, overweight tourists from Down Under. (Australians seem to have edged out Americans as the cinema’s preferred vulgarians.)

Seeking help, Nim turns to her hero Alex Rover, author of a series of globe-trotting adventures in which he escapes one close call after another. What Nim doesn’t know is that Alex is the fictional construct of agoraphobic author Alexandra (Jodie Foster), who can’t even leave her house to get the mail. (Alexandra does come equipped with product placement–friendly neuroses; she’s addicted to Purell Hand Sanitizer and Progresso soup.)

“Alex” had been e-mailing Jack for information about the island’s dormant volcano, but Nim responds to the e-mails, eventually asking for help in fending off the invaders. (Wouldn’t the e-mail about the volcano be a clue to Nim that Alex’s adventures are fictional? Don’t world travelers learn things by actually traveling rather than by Googling?) Encouraged by the fictional Alex — who appears to both Alexandra and Nim in the guise of Gerard Butler — Alexandra ventures out of her San Francisco digs and makes her way to the island.

Breslin manages to make this too-good-to-be-true kid seem real, and Foster clearly relishes this rare opportunity to play some comedy (even if the jokes aren’t always funny). But Butler’s a big stiff in both roles — Jack’s got an unconvincing American accent, and Alex comes off like an Indiana Jones impersonator you might hire for a kid’s birthday party.

Viewers under 10 will have a ball — and boys should certainly be encouraged to see an exciting movie about a clever, resourceful girl’s adventures — but their parents may find themselves envious of anyone who gets to leave this “Island.”